1. Field of the Invention
The invention relates to rotary harrows; and, more particularly, to harrows comprising a plurality of tined soil-working members in side-by-side relationship.
2. Description of the Prior Art
Harrow machines are well known in the farming industry. One such machine, and improvements thereon, is described in U.S. Pat. Nos. 3,899,029 and 3,821,989 to Van Der Lely et al. One of the problems encountered in using such prior art machines is the tremendous vibrations that take place since this machine utilizes an equal total number of rotating tines and the power transfer to such tines is mounted over one of the rotors which rotate the tines. This results in an uneven balance on both sides of the machine. That is, there is more power to the side of the prior art Van Der Lely et al. machines having the lesser number of rotors. More power is necessary to drive the gears for the rotors on the side having the extra rotor. This results in a power lag which causes a vibration in the gear box system of the Van Der Lely et al. machine.
The Van Der Lely et al. machines always contemplate the use of an even number of sets of tines turning clockwise as are turning counterwise. The intent of the prior art Van Der Lely et al. machine is to have no vibration when working the ground. However, in practice, the aforementioned power lag affects the gear box and can shake the machine apart.
Also, with the prior art Van Der Lely et al. machines, there is no way to perform close cultivation since all of the tines are of the same length. If one removed rotors of such prior art machines, a distance of about 20" around a plant would be left which is too great for good cultivation. There would be no way of cultivating in between the beds.